KR20090101954A - Composition and light-emitting element comprising the composition - Google Patents

Abstract

Disclosed is a composition comprising a compound having a pyrazine ring structure and a phosphorescent compound, wherein the compound having a pyrazine ring structure has a pyrazine ring structure represented by the general formula (1), (2) or (3).(1) (2) (3) wherein R and R1 independently represent a hydrogen atom or a univalent group and multiple R's and multiple R1's may be the same as or different from one another. Also disclosed is a polymer having a residue derived from the phosphorescent compound and the pyrazine ring structure.

Description

COMPOSITION AND LIGHT-EMITTING ELEMENT COMPRISING THE COMPOSITION

The present invention relates to a composition comprising a compound having a pyrazine ring structure and a phosphorescent compound, and a light emitting device comprising the composition.

As a luminescent material used for the light emitting layer of a light emitting element, it is known that the element which used the compound which shows light emission from a triplet excited state (henceforth a "phosphorescent compound") for a light emitting layer is high in luminous efficiency. When using a phosphorescent compound for a light emitting layer, the composition which adds the said compound to a matrix is normally used as a luminescent material. As said matrix, since a thin film can be formed by application | coating, a polymer like polyvinylcarbazole can be used preferably (patent document 1). However, such a polymer has a problem that it is difficult to inject electrons because of its high minimum boiling point molecular trajectory (hereinafter sometimes referred to as "LUMO").

On the other hand, conjugated polymers such as polyfluorene have a low LUMO, and thus, when used as a matrix, electrons can be injected relatively easily. However, since the lowest triplet excitation energy is low, such conjugated polymers are not suitable for use as a matrix for shorter wavelength light emission than green, especially, for example, a light emitting material containing polyfluorene and triplet light emitting compounds, which are conjugated polymers. Has low luminous efficiency (Patent Document 2, Non-Patent Document 1).

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-50483

Patent Document 2: Japanese Patent Application Laid-Open No. 2002-241455

Non Patent Literature 1: APPLIED PHYSICS LETTERS, 80, 13, 2308 (2002)

<Start of invention>

Problems to be Solved by the Invention

Accordingly, an object of the present invention is to provide a light emitting material having excellent luminous efficiency when used in the manufacture of light emitting devices and the like.

Means for solving the problem

MEANS TO SOLVE THE PROBLEM As a result of earnestly examining, the present inventors discovered that the composition containing the pyrazine ring structure and the phosphorescent compound solved the problem mentioned above, and came to complete this invention.

That is, the present invention firstly provides a composition comprising a compound having a pyrazine ring structure and a phosphorescent compound.

Secondly, the present invention provides a polymer having the residue of the phosphorescent compound and the pyrazine ring structure.

The present invention provides a light emitting thin film, an organic semiconductor thin film and a light emitting device including the composition or the polymer.

Fourthly, the present invention provides a planar light source including the light emitting element, a segment display device and a dot matrix display device, illumination provided with the light emitting element, and a liquid crystal display device including the light emitting element as a backlight.

Effect of the Invention

The composition of the present invention and the like have high luminous efficiency. Therefore, when the composition etc. of this invention are used for manufacture of light emitting elements, etc., the light emitting element excellent in luminous efficiency is obtained. In addition, the composition and the like of the present invention have relatively excellent luminescence in short wavelength green or blue light emission. This is considered to be because the compound contained in the composition of the present invention and the LUMO of the polymer of the present invention are low, so that electrons are relatively easy to be injected and the minimum triplet excitation energy is large.

Best Mode for Carrying Out the Invention

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

<Composition>

The composition of the present invention contains a compound having a pyrazine ring structure and a phosphorescent compound. The said pyrazine ring structure means the group formed by removing 1-4 hydrogen atoms from the pyrazine which may have a substituent.

As said pyrazine ring structure, the structure represented by the following general formula (1)-(3) and (5)-7, the structure represented by A-1, A-2 mentioned later, are mentioned, for example.

When the compound having a pyrazine ring structure is a polymer having a pyrazine ring structure represented by the following Chemical Formulas 1 to 3, 5 to 7, it is preferable that the compound is a polymer compound having the following pyrazine ring structure in the main chain and / or the side chain. In addition, the said pyrazine ring structure which has in 1 molecule is at least 1 sort (s).

(Wherein R and R ₁ each independently represent a hydrogen atom or a monovalent group, and a plurality of R and R ₁ may be the same or different)

In the formulas (1) to (3), (5) and (6), R and R ₁ each independently represent a hydrogen atom or a monovalent group, and preferably one or more of R (or R ₁ ) present in plural numbers is a monovalent group, and preferably not all of the plurality of existing R (or R ₁₎ to a monovalent group.

As said monovalent group, For example, a halogen atom, an alkyl group, an alkyloxy group, an alkylthio group, the aryl group which may have a substituent, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkyloxy group, an arylalkylthio group Monovalent heterocyclic group which may have an acyl group, an acyloxy group, an amide group, an acid imide group, an imine residue, a substituted amino group, a substituted silyl group, a substituted silyloxy group, a substituted silylthio group, a substituted silylamino group, and a substituent Aryloxy group, heteroarylthio group, aryl alkenyl group, arylethynyl group, substituted carboxyl group, cyano group, etc. are mentioned, Preferably an alkyl group, an alkoxy group, an aryl group which may have a substituent, and may have a substituent It is a monovalent heterocyclic group. In addition, an N-valent heterocyclic group (N is 1 or 2) is formed by removing N hydrogen atoms from a heterocyclic compound. Moreover, as monovalent heterocyclic group, monovalent aromatic heterocyclic group is preferable.

The pyrazine ring structure represented by the above formulas (1) to (3), (5), (6) has a substituent at the position of the bond, an aryl group which may have a substituent, a monovalent heterocyclic group which may have a substituent, an arylene group which may have a substituent, and a substituent In the partial structure which couple | bonds with ring structures, such as a bivalent heterocyclic group which may have, in the said Formulas 1-3, 5, 6, at least 1 of said R is a monovalent group whose total number of atoms other than a hydrogen atom is 3 or more. It is preferable, it is more preferable that it is a monovalent group which is 5 or more, It is still more preferable that the monovalent group which is 7 or more, It is especially preferable that the monovalent group which is 10 or more.

It is also preferable that at least one of R and R _{1 be} an alkyl group, an alkoxy group, a phenyl group which may have a substituent, or a heteroaryl group which may have a substituent, and one or more of R may have an alkyl group, an alkoxy group or a substituent. It is also preferable that it is a phenyl group which exists, or the heteroaryl group which may have a substituent.

As a compound which has the said pyrazine ring structure, the compound which has a residue of the compound represented by following General formula A-1 or A-2 is also mentioned. In addition, the said pyrazine ring structure which has in 1 molecule is at least 1 sort (s).

<Formula A-1>

<Formula A-2>

Wherein Y ¹ is -C (R ^a ) (R ^b )-, -C (= O)-, -N (R ^c )-, -O-, -Si (R ^d ) (R ^e )- , -P (R ^f )-, -S-, -S (= O) _2- , n is an integer of 0 to 5, and Ar ₁ may have a monovalent aryl group or substituent which may have a substituent A monovalent heterocyclic group which is present, and in the case where a plurality of Y ^{1 's} are present, they may be the same or different, and R ^a to R ^f each independently represent a hydrogen atom or a monovalent group, and R has the same meaning as described above, Plural R's may be the same or different)

Examples of the monovalent group represented by R ^a to R ^f are alkyl group, alkoxy group, alkylthio group, aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkoxy group, arylalkylthio group, arylalkenyl group, arylalki And a silyl group, an amino group, a substituted amino group, a silyl group, a substituted silyl group, a silyloxy group, a substituted silyloxy group, a monovalent heterocyclic group, and a halogen atom.

In addition, in view of luminous efficiency, the compound having the pyrazine ring structure preferably has a pyrazine ring structure other than the residue of the compound represented by the following formula (A-3).

<Formula A-3>

(Wherein Z ring is a cyclic structure containing a carbon atom, Z ₁ and Z ₂ , and Z ₁ and Z ₂ each independently represent —C (H) = or —N =)

In said Formula (A-3), the said cyclic structure includes the aromatic ring which may have a substituent, and the non-aromatic ring which may have a substituent, Specifically, a benzene ring, a heterocyclic ring, an alicyclic hydrocarbon ring, and these rings are condensed in multiple numbers The ring formed, the thing by which some hydrogen atoms of these rings were substituted, etc. are mentioned.

The residue of the compound represented by the formulas (A-1) to (A-3) means a group formed by removing part or all of the hydrogen atoms in the compound.

The compound which has the said pyrazine ring structure may contain the other partial structure. The kind of other substructures differs depending on whether they are present at the ends or not. In the case where other partial structures are present at the terminal, the other partial structures are stable monovalent groups, but in view of ease of synthesis and the like, monovalent substituents or hydrogen atoms contained in the R and R ₁ are preferable. When no other substructure is present at the terminal, the other substructure is a stable multivalent group, but a multivalent group having a property of conjugation in terms of the energy level of LUMO is preferable. As such a group, a bivalent aromatic group and a trivalent aromatic group are mentioned specifically ,. An aromatic group is group derived from the organic compound which shows aromaticity here. As such an aromatic group, a phenyl group, a naphthyl group, anthracenyl group, a pyridyl group, a quinolyl group, an isoquinolyl group, etc. are mentioned.

When the compound having a pyrazine ring structure is a polymer, a structure represented by the following formula (4) may be mentioned as one of the other preferable partial structures which may be included in the compound.

The structure represented by the formula (4) is an alkyl group, alkoxy group, alkylthio group, aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkoxy group, arylalkylthio group, arylalkenyl group, arylalkynyl group, amino group, A substituent selected from the group consisting of a substituted amino group, silyl group, substituted silyl group, halogen atom, acyl group, acyloxy group, imine residue, amide group, acid imide group, monovalent heterocyclic group, carboxyl group, substituted carboxyl group and cyano group May have

In Formula 4, the P ring and the Q ring each independently represent an aromatic ring, but the P ring may or may not be present. Two bonds are present on the P ring or Q ring, respectively, when P ring is present, and on the 5- or 6-membered ring or Q ring containing Y, respectively, when P ring is not present. In addition, the 5- or 6-membered ring containing the P ring, Q ring, Y is an alkyl group, alkoxy group, alkylthio group, aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkoxy group, Arylalkylthio group, arylalkenyl group, arylalkynyl group, amino group, substituted amino group, silyl group, substituted silyl group, halogen atom, acyl group, acyloxy group, imine residue, amide group, acid imide group, monovalent heterocyclic group, It may have a substituent selected from the group consisting of a carboxyl group, a substituted carboxyl group and a cyano group. Y is -O-, -S-, -Se-, -B (R ₁ )-, -Si (R ₂ ) (R ₃ )-, -P (R ₄ )-, -PR ₅ (= O)- , -C (R ₆ ) (R ₇ )-, -N (R ₈ )-, -C (R ₉ ) (R ₁₀ ) -C (R ₁₁ ) (R ₁₂ )-, -OC (R ₁₃ ) ( R ₁₄ )-, -SC (R ₁₅ ) (R ₁₆ )-, -NC (R ₁₇ ) (R ₁₈ )-, -Si (R ₁₉ ) (R ₂₀ ) -C (R ₂₁ ) (R ₂₂ )- , -Si (R ₂₃ ) (R ₂₄ ) -Si (R ₂₅ ) (R ₂₆ )-, -C (R ₂₇ ) = C (R ₂₈ )-, -N = C (R ₂₉ )-or -Si ( R ₃₀ ) = C (R ₃₁ )-. R ₁ to R ₃₁ each independently represent a hydrogen atom, an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, an arylalkenyl group, An aryl alkynyl group, an amino group, a substituted amino group, a silyl group, a substituted silyl group, a silyloxy group, a substituted silyloxy group, a monovalent heterocyclic group, or a halogen atom is shown. In this, an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, and a monovalent heterocyclic group are preferable, and an alkyl group, an alkoxy group, an aryl group, and a monovalent heterocyclic group Is more preferable, and an alkyl group and an aryl group are especially preferable.

As a structure represented by the said General formula (4), the structure represented by the following general formula (4-1), (4-2) or (4-3), and the structure represented by the following general formula (4-4) or (4-5) Can be mentioned. In the formulas (4-4) and (4-5), Y is preferably a carbon atom, a nitrogen atom, an oxygen atom or a sulfur atom in terms of obtaining a higher luminous efficiency.

(In the formula, A ring, B ring, and C ring each independently represents an aromatic ring, and formulas (4-1), (4-2) and (4-3) are each an alkyl group, an alkoxy group, an alkylthio group, Aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkoxy group, arylalkylthio group, arylalkenyl group, arylalkynyl group, amino group, substituted amino group, silyl group, substituted silyl group, halogen atom, acyl group, acyl May have a substituent selected from the group consisting of an oxy group, an imine residue, an amide group, an acid imide group, a monovalent heterocyclic group, a carboxyl group, a substituted carboxyl group, and a cyano group, and Y represents the same meaning as above)

(Wherein, D ring, E ring, F ring and G ring are each independently an alkyl group, an alkoxy group, an alkylthio group, an aryl group, an aryloxy group, an arylthio group, an arylalkyl group, an arylalkoxy group, an arylalkylthio group, Aryl alkenyl group, aryl alkynyl group, amino group, substituted amino group, silyl group, substituted silyl group, halogen atom, acyl group, acyloxy group, imine residue, amide group, acid imide group, monovalent heterocyclic group, carboxyl group, substituted carboxyl group and Represents an aromatic ring which may have a substituent selected from the group consisting of a cyano group, and Y represents the same meaning as above)

In the above formulas (4-1), (4-2), (4-3), (4-4) and (4-5), A ring, B ring, C ring, D ring, E ring, F ring And the G ring each independently represent an aromatic ring. Examples of the aromatic ring include aromatic hydrocarbon rings such as benzene ring, naphthalene ring, anthracene ring, tetracene ring, pentacene ring, pyrene ring and phenanthrene ring; And heteroaromatic rings such as pyridine ring, bipyridine ring, phenanthroline ring, quinoline ring, isoquinoline ring, thiophene ring, furan ring and pyrrole ring.

When the compound which has the said pyrazine ring structure is a polymer, group represented by the following general formula is mentioned as one of the other preferable partial structures which may be contained in the said compound.

(In the formula, Ar ₆ , Ar ₇ , Ar ₈ and Ar ₉ each independently represent an arylene group or a divalent heterocyclic group, and Ar ₁₀ , Ar ₁₁ and Ar ₁₂ each independently represent an aryl group or a monovalent heterocyclic group). , Ar ₆ , Ar ₇ , Ar ₈ , Ar ₉ and Ar ₁₀ may have a substituent, and x and y are each independently 0 or 1, and 0 ≦ x + y ≦ 1)

In the present invention, "polymer" means that the same structural unit (repeated unit) is present in at least two or more compounds. In the case where the compound having the pyrazine ring structure is a polymer, the weight average molecular weight of the polystyrene conversion of the compound is preferably 3 × 10 ² or more, more preferably 3 × 10 ² to 1 × 10 ⁷ from the viewpoint of film formability, 1 * 10 <^3> -1 * 10 <^7> is more preferable, and 1 * 10 <^4> -1 * 10 <^7> is especially preferable.

The pyrazole compound having jinhwan structure can be used in a wide emission wavelength range, and that the lowest triplet of the compounds herein (hereinafter also referred to as "T ₁ energy") of energy less than 2.7 eV preferably, more preferably not less than 2.8 eV It is more preferable that it is 2.9 eV or more, It is especially preferable that it is 3.0 eV or more, It is especially preferable that it is 3.1 eV or more. In addition, an upper limit is 5.0 eV normally.

As for the energy level of the lowest unoccupied molecular orbital (LUMO) of the compound which has the said pyrazine ring structure, it is preferable that the absolute value of the energy level of LUMO is 2.1 eV or more, It is more preferable that it is 2.2 eV or more, It is more preferable that it is 2.3 eV or more , 2.4 eV or more is particularly preferred. In addition, an upper limit is 4.0 eV normally.

In the present specification, the T ₁ energy value of the energy level of the LUMO is a value calculated by calculating a scientific method. In the present specification, the structural optimization of the ground state is performed by the HF (Hartree-Fock) method using a quantum chemistry calculation program Gaussian 03 as a calculation scientific method, and the optimized structure. In the above, the values of the T ₁ energy and the energy level of LUMO were calculated using the time dependent density functional method of the B3P86 level. At that time, 6-31 g * was used as a basis function.

It is a case where the compound which has the said pyrazine ring structure is a polymer, and when there is one type of repeating unit which comprises the said compound, when the said unit is A, the said compound is represented by the following formula.

(Wherein n represents polymerization water)

Here, the energy level of LUMO is calculated for the structure of n = 1, 2 and 3, and the value of n = ∞ when linear approximation of the calculated energy level of LUMO as a function of (1 / n) is used as the LUMO of the compound. It is defined as the energy level of. The same applies to the T ₁ energy.

The pyrazole and a case where the compound having the structure jinhwan polymer, when present in multiple repeating units constituting the compound, and defines the existence of the lowest T ₁ energy among all cases where a T ₁ energy of the compound. The energy level of LUMO is defined as the energy level of LUMO in the structure providing the lowest T ₁ energy.

When the compound having a pyrazine ring structure includes a pyrazine ring structure represented by Formula 1, 2, 3, 5, 6 or 7, the partial structure having at least two π conjugated electrons adjacent to the pyrazine ring structure Is preferably present. The backside angle between the pyrazine ring structure represented by the formula (1), (2), (3), (5), (6) or (7) and the (other) partial structure having at least two π conjugated electrons adjacent to the pyrazine ring structure is usually 20. It is at least °, preferably at least 30 °, more preferably at least 40 °, even more preferably at least 50 °, particularly preferably at least 60 °, particularly preferably at least 70 °.

Here, the backside angle in this invention means the angle computed from the optimization structure in a ground state. The dihedral angle is adjacent to the carbon atom (a ₁ ) at the bonding position with the partial structure having at least two π conjugated electrons in the pyrazine ring structure represented by the above formula (1), (2), (3), (5), (6) or (7). It is defined as a carbon atom (a _2), and the atom (a ₄₎ adjacent said pyrazol jinhwan structure and the combination and atoms (a ₃₎ in the coupled position of the structure in it. Here, when a plurality of combinations of atoms (a ₁ , a ₂ , a ₃ , a ₄ ) can be selected, the back angle is calculated for all cases, and the value having the lowest absolute value is the back angle. The atoms (a ₃ ) and (a ₄ ) may be atoms having π conjugated electrons or atoms which do not have, but are preferably atoms having π conjugated electrons, more preferably carbon atoms, nitrogen atoms, silicon atoms, Phosphorus atom. In this specification, it calculates from the optimization structure in the ground state of the said structure calculated | required by a calculation scientific method (namely, the structure in which the generation energy of the said structure becomes minimum).

Preferable examples of the compound having a pyrazine ring structure include a polymer having a repeating unit represented by the formula (1), (2), (3), (5), (6) or (7), or (1), (2), (3), (5), (6) or (7). In addition to the structure mentioned above, the polymer containing any of the structure chosen from an aromatic ring, the 5-membered or more heterocyclic ring containing a hetero atom, an aromatic amine, and the structure represented by the said General formula (4) is mentioned. Moreover, as a compound which has the said pyrazine ring structure, the polymer represented by the following general formula (5-1)-(5-26) is mentioned.

In the following formulas (5-1) to (5-26), R represents a hydrogen atom or a substituent. Substituents for R include halogen atom, alkyl group, alkyloxy group, alkylthio group, aryl group, aryloxy group, arylthio group, arylalkyl group, arylalkyloxy group, arylalkylthio group, acyl group, acyloxy group, amide group , Acid imide groups, imine residues, substituted amino groups, substituted silyl groups, substituted silyloxy groups, substituted silylthio groups, substituted silylamino groups, monovalent heterocyclic groups, heteroaryloxy groups, heteroarylthio groups, aryl alkenyl groups, and aryl groups A tinyl group, a substituted carboxyl group, and a cyano group are illustrated. The plurality of Rs may be the same or different. As R, an alkyl group, an aryl group, an arylalkyl group, and a monovalent heterocyclic group are more preferable.

(Wherein n represents a polymerization number, R has the same meaning as above, and a plurality of R's may be the same or different)

Moreover, the following polymers are mentioned as a specific structure of the compound which has the said pyrazine ring structure.

(Wherein n represents polymerization water)

The following compounds are also mentioned as a compound which has the said pyrazine ring structure.

As said phosphorescent compound, well-known things, such as a triplet light emitting complex, can be used. For example, what has conventionally been used as a low molecular EL luminescent material is mentioned. These are described in Nature, (1998), 395, 151; Appl. Phys. Lett. (1999), 75 (1), 4; Proc. SPIE-Int. Soc. Opt. Eng. (2001), 4105 (Organic Light-Emitting Materials and Devices IV), 119; J. Am. Chem. Soc., (2001), 123, 4304; Appl. Phys. Lett., (1997), 71 (18), 2596; Syn. Met., (1998), 94 (1), 103; Syn. Met., (1999), 99 (2), 1361; Adv. Mater., (1999), 11 (10), 852; Inorg. Chem., (2003), 42, 8609; Inorg. Chem., (2004), 43, 6513; Journal of the SID 11/1, 161 (2003); WO2002 / 066552; WO2004 / 020504; WO2004 / 020448 and the like. Among them, the ratio of the sum of the squares of the orbital coefficients of the outermost d orbits of the center metal in the highest occupied molecular orbital (HOMO) of the metal complex occupies in the sum of the squares of all atomic orbital coefficients is 1/3. The above is preferable from the viewpoint of obtaining high light emission efficiency. For example, an orthometallized complex whose center metal is a transition metal which belongs to a 6th period is mentioned.

As the center metal of the triplet light emitting complex, a reactor having an atomic number of 50 or more, a metal having spin-orbit interaction with the complex and causing crossover between singlet and triplet states, for example, gold , Platinum, iridium, osmium, rhenium, tungsten, europium, terbium, thulium, dysprosium, samarium, praseodymium, gadolinium, yttrium, and the like, but preferably gold, platinum, iridium, osmium, rhenium, tungsten Atoms, more preferably atoms of gold, platinum, iridium, osmium and rhenium, still more preferably atoms of gold, platinum, iridium and rhenium, particularly preferably atoms of platinum and iridium.

Examples of the ligand of the triplet light emitting complex include 8-quinolinol and derivatives thereof, benzoquinolinol and derivatives thereof, 2-phenyl-pyridine and derivatives thereof, and the like.

In view of solubility, the phosphorescent compound is preferably a compound having substituents such as an alkyl group, an alkoxy group, an aryl group which may have a substituent, and a heteroaryl group which may have a substituent. Moreover, it is preferable that the total number of the atoms which removed the hydrogen atom of the said substituent is 3 or more, It is more preferable that the total number is 5 or more, It is further more preferable that it is 7 or more, It is especially preferable that it is 10 or more. In addition, it is preferable that at least one substituent be present in each ligand, and the type of the substituent may be the same or different for each ligand.

The following can be mentioned as said phosphorescent compound.

The amount of the phosphorescent compound in the composition of the present invention is usually 0.01 to 80 parts by weight, preferably 0.1 to 30 parts by weight, more preferably 100 parts by weight of the compound having the pyrazine ring structure. Is 0.1 to 15 parts by weight, particularly preferably 0.1 to 10 parts by weight. In the composition of the present invention, the compound having the pyrazine ring structure and the phosphorescent compound may be used alone or in combination of two or more.

The composition of this invention may contain the arbitrary components other than the compound which has the said pyrazine ring structure, and the said phosphorescent compound in the range which does not impair the objective of this invention. As this arbitrary component, a hole transport material, an electron transport material, antioxidant, etc. are mentioned.

Examples of the hole transport material include aromatic amines, carbazole derivatives, polyparaphenylene derivatives and the like which have been known as hole transport materials for organic EL devices.

Examples of the electron transport material include oxadiazole derivatives, anthraquinomethane and derivatives thereof, benzoquinone and derivatives thereof, naphthoquinone and derivatives thereof, anthraquinone and derivatives thereof, tetra And cyanoanthraquinodimethane and derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, and metal complexes of 8-hydroxyquinoline and derivatives thereof.

In the composition of the present invention, the highest triplet excitation energy (ETP) of the polymer or compound having the pyrazine ring structure and the lowest triplet excitation energy (ETT) of the phosphorescent compound satisfy the following chemical formula It is preferable in terms of efficiency.

ETT> ETP-0.20 (eV)

The luminescent thin film of this invention is obtained by forming the thin film containing the composition of this invention. As a manufacturing method of a thin film, application | coating of a solution, vapor deposition, transfer, etc. are mentioned. Application of the solution includes spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, fiber coating, dip coating, spray coating, screen printing, flex printing, Coating methods, such as an offset printing method and an inkjet printing method, can be used.

It is preferable that the solvent can dissolve or uniformly disperse the composition. Examples of the solvent include chlorine solvents (chloroform, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, chlorobenzene, o-dichlorobenzene, etc.) and ether solvents (tetrahydrofuran, dioxane, etc.) , Aromatic hydrocarbon solvents (toluene, xylene, etc.), aliphatic hydrocarbon solvents (cyclohexane, methylcyclohexane, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, etc.), Ketone solvents (acetone, methyl ethyl ketone, cyclohexanone, etc.), ester solvents (ethyl acetate, butyl acetate, ethyl cellosolve acetate, etc.), polyhydric alcohols and derivatives thereof (ethylene glycol, ethylene glycol monobutyl ether, ethylene Glycol monoethyl ether, ethylene glycol monomethyl ether, dimethoxyethane, propylene glycol, diethoxymethane, triethylene glycol monoethyl ether, glycerin, 1,2-hexanediol, etc., alcohol solvents (methanol, ethanol, propanol, Isov Ropanol, cyclohexanol, etc.), sulfoxide solvents (dimethylsulfoxide, etc.), amide solvents (N-methyl-2-pyrrolidone, N, N-dimethylformamide, etc.) are exemplified and selected from these. Can be used. In addition, these organic solvents may be used individually by 1 type, or may use 2 or more types together.

In the case of using the inkjet printing method, it is possible to use a known method as the selection of the solvent in the solution and the additive in order to improve the ejectability, fluctuation and the like from the head. In this case, it is preferable that the viscosity of a solution is 1-100 mPa * s at 25 degreeC. Moreover, when evaporation is too remarkable, it will become difficult to repeat discharge from a head. In view of the above, preferred solvents to be used include, for example, single or mixed solvents containing anisole, bicyclohexyl, xylene, tetralin and dodecylbenzene. Generally, the solution for inkjets suitable for the composition used by the method of mixing some solvent, the method of adjusting the density | concentration in the solution of a composition, etc. can be obtained.

<Polymer>

The polymer of the present invention has a residue of the phosphorescent compound and the pyrazine ring structure. The pyrazine ring structure is the same as described and exemplified in the section of the composition. As the polymer of the present invention, (1) a polymer having a structure of a phosphorescent compound in the main chain of the polymer, (2) a polymer having a structure of a phosphorescent compound at the end of the polymer, and (3) a structure of a phosphorescent compound in the side chain of the polymer The polymer which has it is mentioned.

<Light emitting element>

Next, the light emitting element of this invention is demonstrated.

The light emitting device of the present invention comprises the composition or the polymer, and usually contains the composition or the polymer at least at a portion between an electrode including an anode and a cathode, but includes them as a light emitting layer in the form of the light emitting thin film. It is desirable to. In addition, from the viewpoint of improving the performance such as luminous efficiency, durability, etc., it may include one or more known layers having other functions. Examples of such a layer include a charge transport layer (ie, a hole transporting layer, an electron transporting layer), a charge blocking layer (ie, a hole blocking layer, an electron blocking layer), a charge injection layer (ie, a hole injection layer, an electron injection layer), a buffer layer, and the like. have. In the light emitting device of the present invention, the light emitting layer, the charge transport layer, the charge blocking layer, the charge injection layer, the buffer layer, and the like may each include one layer or two or more layers.

The light emitting layer is a layer having a function of emitting light. The hole transport layer is a layer having a function of transporting holes. The electron transport layer is a layer having a function of transporting electrons. These electron transport layer and hole transport layer are collectively called charge transport layer. The charge blocking layer is a layer having a function of shielding holes or electrons from the light emitting layer, and a layer for transporting electrons and shielding holes is called a hole blocking layer, and a layer for transporting holes and shielding electrons. It is called the electron blocking layer.

As said buffer layer, the layer containing a conductive polymer adjacent to an anode is mentioned.

As a specific example of the light emitting element of this invention, the structures of the following a) -q) are mentioned.

a) anode / light emitting layer / cathode

b) anode / hole transport layer / light emitting layer / cathode

c) anode / light emitting layer / electron transport layer / cathode

d) anode / light emitting layer / hole blocking layer / cathode

e) anode / hole transport layer / light emitting layer / electron transport layer / cathode

f) anode / charge injection layer / light emitting layer / cathode

g) anode / light emitting layer / charge injection layer / cathode

h) anode / charge injection layer / light emitting layer / charge injection layer / cathode

i) anode / charge injection layer / hole transport layer / light emitting layer / cathode

j) anode / hole transport layer / light emitting layer / charge injection layer / cathode

k) anode / charge injection layer / hole transport layer / light emitting layer / charge injection layer / cathode

l) anode / charge injection layer / light emitting layer / electron transport layer / cathode

m) anode / light emitting layer / electron transport layer / charge injection layer / cathode

n) anode / charge injection layer / light emitting layer / electron transport layer / charge injection layer / cathode

o) anode / charge injection layer / hole transport layer / light emitting layer / electron transport layer / cathode

p) anode / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode

q) anode / charge injection layer / hole transport layer / light emitting layer / electron transport layer / charge injection layer / cathode

(Here, / indicates that each layer is stacked adjacent to each other and is the same below, and the light emitting layer, the hole transporting layer, and the electron transporting layer may each independently use two or more layers)

When the light emitting element of the present invention has a hole transporting layer (usually, the hole transporting layer contains a hole transporting material), a known material can be appropriately selected and used as the hole transporting material. Specific examples thereof include polyvinylcarbazole and its derivatives, polysilane and its derivatives, polysiloxane derivatives having an aromatic amine in the side chain or the main chain, pyrazoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, polyaniline and derivatives thereof, And polymer hole transport materials such as polythiophene and derivatives thereof, polypyrrole and derivatives thereof, poly (p-phenylenevinylene) and derivatives thereof, and poly (2,5-thienylenevinylene) and derivatives thereof. . As the hole transporting material, Japanese Patent Laid-Open No. 63-70257, Japanese Patent Laid-Open No. 63-175860, Japanese Patent Laid-Open No. 2-135359, Japanese Patent No. 2-135361, Japanese Patent No. 2-209988, What is described in Unexamined-Japanese-Patent No. 3-37992, 3-152184, etc. are illustrated.

When the light emitting element of this invention has an electron carrying layer (normally an electron carrying layer contains an electron carrying material), a well-known thing can be suitably selected and used as an electron carrying material. Specific examples thereof include oxadiazole derivatives, anthraquinodimethane and derivatives thereof, benzoquinone and derivatives thereof, naphthoquinone and derivatives thereof, anthraquinone and derivatives thereof, tetracyanoanthraquinodimethane and derivatives thereof, fluorenone derivatives, Diphenyl dicyanoethylene and derivatives thereof, diphenoquinone derivatives, metal complexes of 8-hydroxyquinoline and derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and derivatives thereof, and polyfluorene and derivatives thereof; have.

The film thickness of the hole transport layer and the electron transport layer may be selected so that the optimum value varies depending on the material used, and the driving voltage and the luminous efficiency are appropriate values. However, at least a thickness at which pinholes do not occur is required. It is not preferable because the driving voltage becomes high. Therefore, the film thickness of the hole transport layer and the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

In addition, among the charge transport layers provided adjacent to the electrodes, those having the function of improving the charge injection efficiency from the electrodes and having the effect of lowering the driving voltage of the device are particularly those of the charge injection layers (ie, the hole injection layer and the electron injection layer). Generic terms, which are the same below).

In addition, in order to improve adhesion to the electrode or to improve charge injection from the electrode, the charge injection layer or the insulating layer (usually 0.5 nm to 4 nm in average film thickness, which is the same below) may be provided adjacent to the electrode. In addition, a thin buffer layer may be inserted at the interface of the charge transport layer or the light emitting layer in order to improve the adhesion of the interface, to prevent mixing, and the like.

The order and number of layers to be laminated, and the thickness of each layer can be appropriately selected in consideration of luminous efficiency and device life.

As the charge injection layer, a layer comprising a conductive polymer, a layer provided between the anode and the hole transport layer and comprising a material having an ionization potential having a median value between the anode material and the hole transport material included in the hole transport layer, The layer etc. which are provided between a cathode and an electron carrying layer, and the material which has the electron affinity of the intermediate value between the cathode material and the electron carrying material contained in an electron carrying layer are mentioned.

As a material used for the said charge injection layer, it can select suitably from the relationship with the material of an electrode or an adjacent layer, Polyaniline and its derivative (s), Polythiophene and its derivative (s), Polypyrrole and its derivative (s), Polyphenylenevinylene and its derivative (s) , Polythienylenevinylene and derivatives thereof, polyquinoline and derivatives thereof, polyquinoxaline and derivatives thereof, conductive polymers such as polymers containing an aromatic amine structure in the main chain or side chain, metal phthalocyanine (such as copper phthalocyanine), carbon, and the like Is illustrated.

The insulating layer has a function of facilitating charge injection. As a material of the said insulating layer, a metal fluoride, a metal oxide, an organic insulating material, etc. are mentioned. As a light emitting element provided with the said insulating layer, the light emitting element which provided the insulating layer adjacent to the cathode, and the light emitting element which provided the insulating layer adjacent to the anode are mentioned, for example.

The light emitting element of this invention is normally formed on a board | substrate. When the said board | substrate forms an electrode and forms a layer of organic substance, what is necessary is just what does not change, and board | substrates, such as glass, a plastic, a polymer film, and silicon, are mentioned. In the case of an opaque substrate, it is preferable that the opposite electrode is transparent or translucent.

At least one of the anode and the cathode of the light emitting device of the present invention is usually transparent or translucent. Especially, it is preferable that the anode side is transparent or translucent.

As the material of the anode, a conductive metal oxide film, a semitransparent metal thin film, or the like is usually used. As a specific example, the film | membrane (NESA etc.) manufactured using the electroconductive glass containing indium oxide, zinc oxide, tin oxide, and indium tin oxide (ITO), indium zinc oxide, etc. which are these complexes, gold, , Platinum, silver, copper and the like are used, and ITO, indium zinc oxide and tin oxide are preferable. As a manufacturing method, a vacuum vapor deposition method, sputtering method, an ion plating method, a plating method, etc. are mentioned. Moreover, as said anode, organic transparent conductive films, such as polyaniline and its derivative (s), polythiophene and its derivative (s), can also be used. In addition, the anode may have a laminated structure of two or more layers.

As the material of the negative electrode, a material having a small work function is usually preferable. For example, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium , Metals such as cerium, samarium, europium, terbium and ytterbium, and two or more alloys thereof, or one or more of these and one of gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin Alloys with two or more, graphite or graphite intercalation compounds and the like. Examples of the alloy include a magnesium-silver alloy, a magnesium-indium alloy, a magnesium-aluminum alloy, an indium-silver alloy, a lithium-aluminum alloy, a lithium-magnesium alloy, a lithium-indium alloy, a calcium-aluminum alloy, and the like. The cathode may also have a laminated structure of two or more layers.

The light emitting element of the present invention can be used as a planar light source, a display device (segment display device, dot matrix display device, liquid crystal display device, etc.), its backlight (such as a liquid crystal display device having the light emitting element as a backlight), or the like. .

In order to obtain planar light emission using the light emitting device of the present invention, the planar anode and cathode may be disposed to overlap each other. In addition, in order to obtain pattern light emission, a method of providing a mask having a patterned window on the surface of the planar light emitting device, an extremely thick organic material layer of the non-light emitting part, and making it substantially non-emission, among the anode or the cathode There is a method of forming one or both electrodes in a pattern shape. By forming a pattern by any of these methods, and arrange | positioning so that several electrodes can turn ON / OFF independently, the segment type display element which can display a number, a letter, a simple symbol, etc. is obtained. In addition, in order to form a dot matrix element, the anode and the cathode may be formed in a stripe shape and arranged so as to cross at right angles. The partial color display and the multi-color display are possible by the method of apply | coating partly the polymeric fluorescent substance from which several light emission colors differ, or the method of using a color filter or a fluorescence conversion filter. The dot matrix element can be passively driven or can be actively driven in combination with a TFT or the like. These display elements can be used as display devices such as computers, televisions, portable terminals, mobile phones, car navigation systems, and view finders of video cameras. In addition, the planar light emitting element is a spontaneous light thin type, and can be suitably used as a planar light source for backlight of a liquid crystal display device or a planar illumination light source. Moreover, when a flexible board | substrate is used, it can be used also as a curved light source or a display apparatus.

The composition and the polymer of the present invention are not only useful for the production of devices, but can also be used as semiconductor materials such as organic semiconductor materials, light emitting materials, optical materials, and conductive materials (for example, applied by doping). Therefore, a film, such as a luminescent thin film, a conductive thin film, an organic semiconductor thin film, can be manufactured using the said composition and a polymer.

The composition and the polymer of the present invention can form and elementize the conductive thin film and the semiconductor thin film by the same method as the method for producing the light emitting thin film used in the light emitting layer of the light emitting device. It is preferable that the larger of an electron mobility or a hole mobility is a semiconductor thin film of ^10-5 cm <2> / V / sec or more. The organic semiconductor thin film can be used for organic solar cells, organic transistors, and the like.

Hereinafter, although an Example is shown in order to demonstrate this invention further in detail, this invention is not limited to this.

<Example 1>

The lowest triplet excitation energy T ₁ (1 / n = 0), which is an extrapolation value at n = ∞ of the polymer (P-1) represented by the above formula, is 3.1 eV, and is the absolute value E of the energy level of the lowest boiling point molecular orbit. _LUMO (1 / n = 0) was 2.3 eV. The back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (pyrazine ring in this example) was 61 degrees.

The calculation of the parameters was carried out by the calculation scientific method described in the detailed description of the invention. Specifically, the following repeating unit (M-1) in the polymer (P-1) was simplified with (M-1a), and structural optimization was performed by the HF method.

At that time, 6-31 G * was used as a basis function. Then, using the same basis, the energy level of the lowest unoccupied molecular orbit and the lowest triplet excitation energy were calculated by the B3P86 level time dependent density functional method. The feasibility of simplifying the chemical structure was confirmed by the method described in Japanese Unexamined Patent Publication No. 2005-126686 by the fact that the alkyl side chain length dependency on the energy level of the lowest triplet excitation energy and the lowest boiling point molecular orbit was small ( The same below). In addition, the said back angle was computed using the structure optimized structure in trimer (in the case of n = 3).

If a light emitting element is manufactured using the composition containing a polymer (P-1) and a phosphorescent compound, it is excellent in luminous efficiency.

<Example 2>

The lowest triplet excitation energy T ₁ (1 / n = 0), which is an extrapolation value at n = ∞ of the polymer (P-2) represented by the above formula, is 2.9 eV and is the absolute value E of the energy level of the lowest boiling point molecular orbit. _LUMO (1 / n = 0) was 2.1 eV. The following simplified repeating unit (M-2a) was used for the calculation. The backside angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (fluorene skeleton in this embodiment) was 62 °.

When a light emitting element is manufactured using the composition containing a polymer (P-2) and a phosphorescent compound, light emission efficiency is excellent.

<Example 3>

The lowest triplet excitation energy T ₁ (1 / n = 0), which is an extrapolation at n = ∞ of the polymer (P-3) substantially represented by the above formula, is 2.88 eV to 2.9 eV, and the energy of the lowest boiling point molecular orbital. The absolute value E _LUMO (1 / n = 0) of the level was 2.3 eV. The back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 49 °. In addition, the back surface angle between the benzene ring and the benzene ring adjacent to it was 44 degrees. The following simplified repeating unit (M-3a) was used for the calculation.

For the polymer substantially represented by the formula (P-3), there are two kinds of repeating units constituting the polymer, and in addition to the above-mentioned simplified repeating unit (M-3a), the following simplified repeating unit (M-3b) Also considered, the lowest triplet excitation energy T ₁ (1 / n = 0), which is an extrapolation at n = ∞, is calculated from the repeating unit (M-3b), and is the lowest from 2.89 eV to 2.9 eV. The absolute value E _LUMO (1 / n = 0) of the energy level of the boiling point molecular orbit was 2.3 eV. The lowest triplet excitation energy T _{1, which} is an extrapolation value at n = ∞, is the calculated value (2.88 eV) obtained using the repeating unit (M-3a), and the calculated value obtained using the repeating unit (M-3b). Since it is smaller than (2.89 eV), the absolute value E _LUMO of the lowest triplet excitation energy and the lowest boiling point molecular orbital energy level of the polymer (P-3) are calculated values obtained using the repeating unit (M-3a), respectively. 2.9 eV and 2.3 eV.

<Example 4>

About a THF solution (0.05 wt%) of the phosphorescent compound (MC-1) represented by the above formula, about 5 times by weight of a THF solution (about 1 wt%) of the compound represented by the following formula (6-1) was mixed. . 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-1>

The lowest triplet excitation energy T ₁ of the compound represented by Chemical Formula 6-1 was 3.4 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.0 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 59 degrees.

In addition, the compound represented by the said Chemical formula 6-1 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2004-292432. In addition, the formula MC-1 was synthesized according to the method described in WO02 / 066552.

<Example 5>

To a THF solution (0.05 wt%) of the phosphorescent compound (MC-1), a THF solution (about 1 wt%) of a compound represented by the following formula (6-2) of about 5 times the weight was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-2>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-2 was 3.4 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.1 eV. Moreover, the back surface angle between the pyrazine ring and the partial structure adjacent to the said pyrazine ring (benzene ring in a present Example) was 60 degrees.

In addition, the compound represented by the said Chemical formula 6-2 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2004-292432.

<Example 6>

To a THF solution (0.05 wt%) of the phosphorescent compound (MC-1), about 5 times the THF solution (about 1 wt%) of the compound represented by the following formula (6-3) was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-3>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-3 was 3.3 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.2 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 59 degrees.

In addition, the compound represented by the said Chemical formula 6-3 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2004-292432.

<Example 7>

About a THF solution (0.05 weight%) of the phosphorescent compound (MC-1), about 5 times the weight of the THF solution (about 1 weight%) of the compound represented by following formula (6-4) was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-4>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-4 was 3.4 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.0 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 62 degrees.

In addition, the compound represented by the said Chemical formula 6-4 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2004-292432.

<Example 8>

About a THF solution (0.05 weight%) of the phosphorescent compound (MC-1), about 5 times the weight of the THF solution (about 1 weight%) of the compound represented by following formula (6-5) was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-5>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-5 was 3.4 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.0 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 62 degrees.

In addition, the compound represented by the said Chemical formula 6-5 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2004-292432.

Example 9

About a THF solution (0.05 weight%) of the phosphorescent compound (MC-1), about 5 times the weight of the THF solution (about 1 weight%) of the compound represented by following formula (6-6) was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-6>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-6 was 2.9 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.4 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 77 °, and the back angle between two ring structures other than the pyrazine ring was 89 °.

In addition, the compound represented by the said Chemical formula 6-6 was synthesize | combined by the method of Unexamined-Japanese-Patent No. 2007-254456.

<Example 10>

To a THF solution (0.05 wt%) of the phosphorescent compound (MC-1), a THF solution (about 1 wt%) of a compound represented by the following formula (6-7) of about 5 times the weight was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-7>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-7 was 3.3 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 1.5 eV.

<Example 11>

About THF solution (0.05 weight%) of the phosphorescent compound (MC-1), about 5 times the weight of the THF solution (about 1 weight%) of the compound represented by following formula (6-8) was mixed. It dripped at 10 microliters FMF slide glass of the obtained solution, and air dried, and obtained the solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-8>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-8 was 3.6 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 2.0 eV.

<Example 12>

About THF solution (0.05 weight%) of the phosphorescent compound (MC-1), about 5 times the weight of the THF solution (about 1 weight%) of the compound represented by following formula (6-9) was mixed. 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

<Formula 6-9>

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-9 was 3.6 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 1.8 eV.

Example 13

In Example 4, a solution was prepared in the same manner as in Example 4 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet light was irradiated. Blue light emission from (MC-2, American Daisos Corporation, trade name: ADS065BE) was observed.

<Example 14>

In Example 5, a solution was prepared in the same manner as in Example 5 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

<Example 15>

In Example 6, the solution was prepared in the same manner as in Example 6 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

<Example 16>

In Example 7, a solution was prepared in the same manner as in Example 7 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

<Example 17>

In Example 8, a solution was prepared in the same manner as in Example 8 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

Example 18

In Example 9, a solution was prepared in the same manner as in Example 9 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet light was irradiated. Blue emission from (MC-2) appeared.

Example 19

In Example 10, a solution was prepared in the same manner as in Example 10 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

Example 20

A solution was prepared in the same manner as in Example 11 except that the following phosphorescent compound (MC-2) was used in place of the phosphorescent compound (MC-1) and irradiated with ultraviolet light, and the phosphorescent compound was obtained. Blue emission from (MC-2) appeared.

Example 21

In Example 12, a solution was prepared in the same manner as in Example 12 except that the following phosphorescent compound (MC-2) was used instead of the phosphorescent compound (MC-1), and the ultraviolet ray was irradiated. Blue emission from (MC-2) appeared.

<Example 24>

In the air, 10.0 g (62.8 mmol) of 2-aminocaprylic acid and 100 ml of ethylene glycol were added, and heated at 200 ° C. and stirred for 5 hours. After the completion of the reaction, the obtained reaction solution was cooled to room temperature, 100 ml of water was added, and the precipitated solid was filtered and washed with diethyl ether, whereby 3,6-dihexyl diketopiperazine 8.46 represented by the following chemical formula was found. g (yield 44.52%) was obtained as a white solid.

Under argon atmosphere, 1.00 g (3.54 mmol) of 3,6-dihexyl diketopiperazine and 3.03 g (10.62 mmol) of phosphoryloxytribromide were heated to 100 ° C. and stirred for 15 minutes. The resulting mixture was dissolved in 200 mL of chloroform, and then the organic phase was washed with an aqueous sodium hydroxide solution, followed by separation, and then the organic phase was dried over anhydrous sodium sulfate. After distilling off the organic solvent under reduced pressure, a crude product was obtained. The crude product obtained by performing this operation three times was combined and purified by silica gel chromatography (toluene / hexane = 2/1). 2-bromo-3,6-dihexylpyrazine 2.00 represented by the following chemical formula g (yield: 57.9%) was obtained as an oil.

Under argon atmosphere, 0.119 g (0.5 mmol) of 2,7-bis (1,3,2-dioxaborolan-2-yl) -9,9-dioctylfluorene, 2-bromo-3,6- 0.360 g (1.1 mmol) of dihexylpyrazine, tetrakistriphenylphosphinepalladium (12 mg, 0.01 mmol), 2.4 ml of toluene degassed with argon, and 1.3 ml of a 17.5 wt% aqueous solution degassed with argon were added. The mixture was heated to reflux and stirred for 11 hours. 10 mL of toluene was added to the obtained mixture, the organic phase was washed with ion-exchanged water, and after separating, the organic phase was dried over anhydrous sodium sulfate. After distilling off the organic solvent under reduced pressure, 0.432 g of a yellow oil was obtained. The resulting crude product was purified by silica gel chromatography (ethyl acetate / hexane = 7/93) to give 43.7 mg (yield: 9.9%) of the compound represented by the following formula (6-10) as a pale yellow oil.

<Formula 6-10>

<Example 25>

65 nm by spin coating a hole injection layer using a suspension of poly (3,4) ethylenedioxythiophene / polystyrenesulfonic acid (manufactured by Bayer, trade name: BaytronP AI4083) on a glass substrate having a thickness of 150 nm by sputtering method. It was formed into a film with a thickness of and dried at 200 ° C. for 10 minutes on a hot plate. Next, the compound (6-10) obtained above was dissolved in xylene, and the concentration was 3.5% by weight. In addition, the phosphorescent compound (MC-1) was also dissolved in xylene as a phosphorescent material, and the concentration was 3.5% by weight. In addition, a solution was prepared in which the compound (6-10) obtained above and the phosphorescent compound (MC-1) were mixed in a weight ratio of 70/30. This mixed solution was spin coated on the hole injection layer at 1200 rpm. The film thickness of this light emitting layer was usually 80 nm. Then, after drying for 10 minutes at 90 degreeC in nitrogen atmosphere whose water concentration and oxygen concentration are 10 ppm or less, about 5 nm of barium and then about 100 nm of aluminum were vapor-deposited as a cathode, and the EL element was manufactured. The device configuration is ITO / Baytron P (65 nm) / (Compound (6-10) / Phosphorescent Compound (MC-1) = 70/30 (80 nm)) / Ba / Al. Further, after the degree of vacuum reached 1 × 10 ⁻⁴ Pa or less, vapor deposition of the metal was started.

When voltage was applied to the obtained device, green light emission with a peak wavelength of 520 nm derived from the phosphorescent compound (MC-1) was shown. The maximum luminous efficiency of this device was 1.80 cd / A.

The lowest triplet excitation energy T ₁ of the compound represented by Formula 6-10 was 3.0 eV, and the absolute value E _LUMO of the energy level of the lowest boiling point molecular orbit was 1.9 eV. In addition, the back angle between the pyrazine ring and the partial structure adjacent to the pyrazine ring (benzene ring in this example) was 61 degrees.

Example 26

10 µl of the mixed solution containing the compound (6-10) and the phosphorescent compound (MC-1) was added dropwise to the slide glass and air dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

Comparative Example 1

The lowest triplet excitation energy T ₁ (1 / n = 0), which is an extrapolation at n = ∞ of the polymer represented by the above formula (CP-4), is 2.6 eV, and is the absolute value E of the energy level of the lowest boiling point molecular orbit. _LUMO (1 / n = 0) was 2.1 eV. The following simplified repeating unit (CM-4) was used for the calculation. The back angle between adjacent repeating units represented by the following formula (CM-4) was 45 °.

When the light emitting device is manufactured using the composition containing the polymer (CP-4) and the phosphorescent compound, it can be confirmed that the luminous efficiency is inferior as compared with the light emitting devices prepared in Examples 1 to 3.

Comparative Example 2

65 nm by spin coating a hole injection layer using a suspension of poly (3,4) ethylenedioxythiophene / polystyrenesulfonic acid (manufactured by Bayer, trade name: BaytronP AI4083) on a glass substrate having a thickness of 150 nm by sputtering method. It formed into a film at the thickness of and dried at 200 degreeC for 10 minutes on the hotplate. Next, the compound (CP-4) was dissolved in xylene, and the concentration was 1.0% by weight. In addition, the phosphorescent compound (MC-1) was also dissolved in xylene as a phosphorescent material to have a concentration of 1.0% by weight. In addition, a solution was prepared in which the compound (CP-4) obtained above and the phosphorescent compound (MC-1) were mixed in a weight ratio of 70/30. This mixed solution was spin coated on the hole injection layer at 800 rpm. The film thickness of this light emitting layer was 70 nm. Then, after drying for 10 minutes at 90 degreeC in nitrogen atmosphere whose water concentration and oxygen concentration are 10 ppm or less, about 5 nm of barium and then about 100 nm of aluminum were vapor-deposited as a cathode, and the organic electroluminescent element was produced. The device configuration is ITO / Baytron P (65 nm) / (Compound (CP-4) / Phosphorescent Compound (MC-1) = 70/30 (70 nm)) / Ba / Al. Further, after the degree of vacuum reached 1 × 10 ⁻⁴ Pa or less, vapor deposition of the metal was started.

When voltage was applied to the obtained device, peak wavelengths of 440 nm derived from CP-4 and 520 nm derived from MC-1 were simultaneously observed. The maximum luminous efficiency of this device was 0.34 cd / A. Compound (CP-4) was synthesized by the method described in US Pat.

Comparative Example 3

10 μl of the mixed solution containing the compound (CP-4) and the phosphorescent compound (MC-1) was added dropwise to the slide glass and air dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, it became dark compared with the light emission from the said compound (CP-4), and the color difference was hardly seen.

<Reference Example>

10 microliters of xylene solutions (concentration 1.0 wt%) of the said compound (CP-4) were dripped at the slide glass, and air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, the bright blue light emission from the said compound (CP-4) was confirmed.

Example 27

300 mg of 1,4-dimethyl-2,5-di (4 ', 4', 5 ', 5'-tetramethyl [1', 3 ', 2'] dioxaborolan-2'-yl) benzene 452 mg of 2,5-dibromopyrazine, 267 mg of sodium carbonate, and a small amount of bis (triphenylphosphine) palladium (II) dichloride were dissolved in 7 mL of tetrahydrofuran under an argon stream, 4 mL of water was added, and about 70 After stirring for 3 hours at ℃, washed with water and extracted with chloroform. The polymer was separated from the extract.

About 5 times the weight of THF solution (about 1 weight%) of the said polymer was mixed with respect to THF solution (0.05 weight%) of the phosphorescent compound (MC-1). 10 microliters of the obtained solution was dripped at the slide glass, and it air-dried to obtain a solid film. When the ultraviolet-ray of 365 nm was irradiated to this, green light emission from the said phosphorescent compound (MC-1) appeared.

Claims (21)

A composition comprising a compound having a pyrazine ring structure and a phosphorescent compound. The composition according to claim 1, wherein the compound having a pyrazine ring structure is a polymer having a pyrazine ring structure. The composition according to claim 1 or 2, wherein the compound having a pyrazine ring structure has a pyrazine ring structure represented by the following general formula (1), (2) or (3). <Formula 1> <Formula 2> <Formula 3> (Wherein R and R ₁ each independently represent a hydrogen atom or a monovalent group, and a plurality of R and R ₁ may be the same or different) The composition according to claim 1 or 2, wherein the compound having a pyrazine ring structure has a pyrazine ring structure represented by the following Formula (5), (6) or (7). <Formula 5> <Formula 6> <Formula 7> (Wherein, R and R ₁ have the same meaning as above, and a plurality of R ₁ may be identical or different) The composition according to claim 3 or 4, wherein at least one of R is a total number of atoms other than hydrogen atoms of three or more. The composition according to any one of claims 3 to 5, wherein at least one of R and R ₁ is an alkyl group, an alkoxy group, a phenyl group which may have a substituent, or a heteroaryl group which may have a substituent. The compound having the pyrazine ring structure according to any one of claims 3 to 6, wherein the compound having the pyrazine ring structure is adjacent to the pyrazine ring structure represented by the formula (1), 2, 3, 5, 6 or 7 and the pyrazine ring structure. The composition which has a partial structure which has at least two (pi) conjugated electrons, and whose back angle between the said pyrazine ring structure and the said partial structure is 20 degrees or more. The composition according to claim 7, wherein the backside angle between the pyrazine ring structure and the partial structure is 40 ° or more. The composition according to any one of claims 1 to 8, wherein the compound having a pyrazine ring structure has a residue of a compound represented by the following formula (A-1) or (A-2). <Formula A-1> <Formula A-2> Wherein Y ¹ is -C (R ^a ) (R ^b )-, -C (= O)-, -N (R ^c )-, -O-, -Si (R ^d ) (R ^e )- , -P (R ^f )-, -S-, -S (= O) _2- , n is an integer of 0 to 5, and Ar ₁ may have a monovalent aryl group or substituent which may have a substituent A monovalent heterocyclic group which is present, and in the case where a plurality of Y ^{1 's} are present, they may be the same or different, and R ^a to R ^f each independently represent a hydrogen atom or a monovalent group, and R has the same meaning as described above, Plural R's may be the same or different) The composition according to any one of claims 1 to 9, wherein the lowest triplet excitation energy of the compound having the pyrazine ring structure calculated by the calculation chemical technique is larger than 2.7 eV. The composition according to any one of claims 1 to 10, wherein the absolute value of the energy level of the lowest unoccupied molecular orbital of the compound having the pyrazine ring structure calculated by the calculation chemical technique is 2.1 eV or more. The lowest triplet excitation energy (ETP) of the compound having the pyrazine ring structure and the lowest triplet excitation energy (ETT) of the phosphorescent compound satisfy the following formula. Composition to make. <Equation 1> ETT> ETP-0.20 (eV) A polymer having a residue of the phosphorescent compound and the pyrazine ring structure. The light emitting thin film containing the composition of any one of Claims 1-12, or the polymer of Claim 13. An organic semiconductor thin film comprising the composition according to any one of claims 1 to 12 or the polymer according to claim 13. The light emitting element containing the composition as described in any one of Claims 1-12, or the polymer as described in Claim 13. The planar light source provided with the light emitting element of Claim 16. A segment display device comprising the light emitting element according to claim 16. A dot matrix display device comprising the light emitting element according to claim 16. A liquid crystal display device comprising the light emitting element according to claim 16 as a backlight. Illumination provided with the light emitting element of Claim 16.